Provided are a light receiving element etc. which have a high responsivity over the near- to mid-infrared region and stably have a high quality while maintaining the economical efficiency. The light receiving element includes an InP substrate that is transparent to light having a wavelength of 3 to 12 μm, a middle layer that is epitaxially grown on the InP substrate, a GaSb buffer layer located in contact with the middle layer, and a light-receiving layer that is epitaxially grown on the GaSb buffer layer and that has a type-II multiple quantum well structure. The GaSb buffer layer is epitaxially grown on the middle layer while exceeding a range of a normal lattice-matching condition.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A light receiving element formed by using a group III-V compound semiconductor, the light receiving element comprising: an InP substrate that is transparent to light having a wavelength of 3 to 12 μm; a middle layer that is epitaxially grown on the InP substrate; a buffer layer located in contact with the middle layer; and a light-receiving layer that is epitaxially grown on the buffer layer and that includes a type-II multiple quantum well structure having a cutoff wavelength of 3 μm or more, wherein the buffer layer is epitaxially grown on the middle layer while a value of |a 1 −a 0 |/a 0 is within a range of a normal lattice-matching condition, and values of |a 2 −a 1 |/a 1 and |a 2 −a 0 |/a 0 exceed the range of the normal lattice-matching condition, where a 2 represents a lattice constant of the buffer layer, a 1 represents a lattice constant of the middle layer, and a 0 represents a lattice constant of the InP substrate; and the buffer layer is constituted by a GaSb layer, wherein both of the III-group and V-group elements of the buffer layer are different from those of the InP substrate; and the middle layer is an InGaAs layer or a GaAsSb layer.
2. The light receiving element according to claim 1 , wherein the middle layer has a thickness of 50 nm or more.
3. The light receiving element according to claim 1 , wherein the light-receiving layer has a p-n junction therein.
4. The light receiving element according to claim 1 , wherein the light-receiving layer includes an insertion layer that is composed of a group III-V compound semiconductor and that is lattice-matched with the light-receiving layer, and a bottom of a conduction band of the insertion layer is higher than a bottom of a conduction band of the light-receiving layer.
5. The light receiving element according to claim 1 , wherein the multiple quantum well structure is any of {(InAs/GaSb), (InAs/InGaSb), (InAsSb/GaSb), and (InAsSb/InGaSb)} which are type-II multiple quantum well structures.
6. A detecting device comprising the light receiving element according to claim 1 ; and a read-out integrated circuit (ROIC), wherein a pixel electrode in the light receiving element is connected to a read-out electrode in the ROIC with a bump interposed therebetween.
7. A semiconductor epitaxial wafer formed by using a group III-V compound semiconductor, the semiconductor epitaxial wafer comprising: an InP substrate that is transparent to light having a wavelength of 3 to 12 μm; a middle layer that is epitaxially grown on the InP substrate; a GaSb buffer layer located in contact with the middle layer; and a light-receiving layer that is epitaxially grown on the GaSb buffer layer and that has a type-II multiple quantum well structure, wherein the GaSb buffer layer is epitaxially grown on the middle layer while a value |a 1 −a 0 |/a 0 is within a range of a normal lattice-matching condition, and values of |a 2 −a 1 |/a 1 and |a 2 −a 0 |/a 0 exceed the range of the normal lattice-matching condition, where a 2 represents a lattice constant of the buffer layer, al represents a lattice constant of the middle layer, and a 0 represents a lattice constant of the InP substrate, wherein both of the III-group and V-group elements of the GaSb buffer layer are different from those of the InP substrate; and the middle layer is an InGaAs layer or a GaAsSb layer.
8. A method for manufacturing a light receiving element in which a group III-V compound semiconductor is stacked, the method comprising the steps of: preparing an InP substrate that is transparent to light having a wavelength of 3 to 12 μm; epitaxially growing an InGaAs layer or a GaAsSb layer as a middle layer on the InP substrate; epitaxially growing a GaSb buffer layer on the middle layer; and forming, on the GaSb buffer layer, a light-receiving layer including a type-II multiple quantum well structure having a cutoff wavelength of 3 μm or more, wherein the multiple quantum well structure is any of {(InAs/GaSb), (InAs/InGaSb), (InAsSb/GaSb), and (InAsSb/InGaSb)} which are type-II multiple quantum well structures, wherein both of the III-group and V-group elements of the GaSb buffer layer are different from those of the InP substrate.
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
May 16, 2013
July 12, 2016
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